Accompanied with the necessity of redundancy which accompanies an increase in capacity of an internal SRAM, the necessity of separately tuning an LCD driver etc after it has been mounted on a board and the expansion in various usages of individual identification information (ID code, keys for encryption decoding and IC card numbers etc) there is an increased necessity for low cost fuses. Conventionally, as a fuse memory which can be formed by a standard CMOS process, there were memories which include polysilicon or wire metal layers which are melted a laser or a current and there were also memories which include insulation gate layers which are damaged by a voltage.
However, a fuse memory which includes parts which melt or insulation parts which break in this way are not suitable for the purposes required by reprogramming stated above because such fuse memories can only be programmed once. However, while floating gate type nonvolatile memory elements can create fuses which can be electrically erased and programmed, because additional processes are required to be introduced to a standard CMOS process similar to a conventional flash memory for forming a floating gate, they are not adequate in terms of cost. Therefore, a variety of proposals have been made for realizing a floating gate type nonvolatile semiconductor element by a standard CMOS process (one layer polysilicon).